Absorbent articles of the above mentioned kind are intended to absorb and retain body exudates, like urine, faeces and menstrual fluid. Typically, such absorbent articles include an absorbent core sandwiched between a liquid-permeable topsheet and a liquid-impermeable backsheet. Body fluids, especially urine, easily penetrate the liquid-permeable topsheet and are absorbed and retained by the absorbent core. However, body exudates in solid or semi-solid state, such as fecal materials, can normally not penetrate the liquid-permeable topsheet. Thereby, the fecal materials are not isolated within the articles, which results in the fecal materials remaining on the topsheet.
The fact that fecal materials are not isolated within the above mentioned kind of absorbent articles may result in leakage, for example, at the waist regions or the leg openings. In order to reduce the leakage risk, many absorbent articles of the above mentioned kind include means, such as elasticized waistbands and leg cuffs, for inhibiting body exudates in solid or semi-solid state from leaking out of the articles. Furthermore, additional barrier flaps are often provided between the leg openings and the absorbent core to further inhibit leakage.
In addition, the fact that fecal materials are not isolated within absorbent articles, but remain on the topsheet, results in contact between the fecal materials and the skin of the users. It is well-known that contact between fecal materials and the skin of users often give rises to skin irritation and severe discomfort for the users. For example, it may give rise to diaper rash.
It is known to deal with fecal materials by providing a topsheet that conforms closely to the wearer and which has a large aperture that is intended to register with the anal opening, so that fecal material passes through the aperture into a void space, where it is kept isolated from the wearer. Examples of such diapers are shown in U.S. Pat. No. 5,957,907 and WO2008029331
However, these attempts do not solve the problem of handling and retaining low-viscosity fecal material that is prevalent in younger children, especially those who are breast fed, and persons suffering from diarrhea. Low-viscosity fecal material easily moves around on the user facing side of the topsheet under the influence of gravity, motion and pressure by the user. The migration of the fecal material often moves it to the perimeter of the article, increasing the likelihood of leakage, and further smears it against the skin of the user making cleanup more difficult. However, there are different attempts known today trying to solve the problem of handling and retaining low-viscosity fecal material.
One attempt of dealing with low-viscosity fecal matter is described in U.S. Pat. No. 5,342,338, which discloses a topsheet having apertures large enough for low-viscosity fecal material to pass through to a secondary topsheet. The secondary topsheet immobilizes the fecal material in position for dewatering.
Another attempt is described in WO 2006/071143 disclosing an absorbent article having improved properties for handling low-viscosity fecal material. The article includes an inner cover including a three-dimensionally structured hydrophilic fibrous web material having a plurality of recessed and elevated portions. Both the recessed and elevated portions are hydrophilic. Low-viscosity fecal material adheres effectively to the structured hydrophilic fibrous web resulting in immobilization of the faeces. The three-dimensional shaping of the web material may be accomplished by means of e.g. vacuum forming, heat embossing or printing with a bonding agent.
WO 99/55273 describes an apertured laminate web, which may be used as a topsheet in an absorbent article and which is told to be adapted to handle low-viscosity fecal material. The laminate web is formed of first and second liquid pervious materials each having apertures with a defined effective size. The apertures of the first and second materials are aligned and the second material preferably has a hydrophilicity that is greater than the hydrophilicity of the first material. The apertured laminate web is formed by simultaneously bonding and aperturing the first and second materials.
EP 1138301 discloses an absorbent article including an absorbent upper panel attached to an outer surface of a topsheet. The panel is arranged for handling and retaining fecal material, e.g. loose passage, and is made of a fibrous web including a low density fibrous layer that is overlaid by a high density fibrous layer. Also, the panel includes a plurality of openings extending through the thickness. Within the openings, moisture content of loose passage permeates into the topsheet and is absorbed by the core while solid content of loose passage present in the openings permeates into the low density fibrous layer. The fibrous web of the panel may be produced by a process including accumulation of fibres on a moving conveyor provided with a plurality of pins shaped in conformity of the openings.
However, there is still a need for alternative methods for producing a material for retaining faeces, in particular for immobilization of low-viscosity fecal material, which material for retaining faeces is adapted to be used in an absorbent article.